This application relates to an oil system for providing oil to a gear associated with a geared turbofan in a gas turbine engine.
Gas turbine engines are known, and typically include a fan delivering air into a compressor section. Compressed air from the compressor section is delivered into a combustion section, mixed with fuel, and ignited. Products of this combustion pass downstream over turbine rotors which are driven to rotate.
A low pressure turbine rotor drives a low pressure compressor, and traditionally has driven a fan at the same rate of speed. More recently, a gear reduction has been included between the low pressure turbine and the fan such that the fan and the low pressure compressor can rotate at different speeds. Oil management systems typically provide oil to engine bearings and other locations within the engine. As a result of gears being added to turbofan engines, additional components require cooling, thereby necessitating new cooling systems and methodologies. Heat exchangers are utilized in such systems to maintain lubricant within desired thermal limits.
A heat exchanger may be utilized airflow to cool the lubricant. The heat exchanger is sized based on the available airflow during all operational conditions. Air flow available for cooling at low power static conditions may not be as much as is available during higher power flight conditions. The heat exchanger is necessarily increased in size to compensate for the lower airflow while maintaining the desired heat exchange capabilities.
Large heat exchanges provided based on lower power and operation inflicts a weight penalty that can reduce the efficiencies provided by the gear reduction. Accordingly, it is desirable to design and develop devise that provide the heat exchange capability while improving engine operating efficiency.
These and other features disclosed herein can be best understood from the following specification and drawings, the following of which is a brief description.